Perfusion, cardiovascular & Peripheral Vascular Flashcards
Perfusion
Passage of fluid through the circulatory system or lymphatic system to an organ or tissue.
Cardiac output
Volume of blood pumped by the heart in one minute
CO= stroke volume (ml/beat) x heart rate (beats/min)= ml/min
Ejection fraction
The % of blood pumped out the left ventricle with each contraction
Normal: > 50%
Heart failure: < 40%
Blood pressure
Force exerted by the blood against the vessel walls.
**BP must be adequate to maintain tissue perfusion during activity and rest.
Normal= 120/80
Pulse pressure
Difference between systolic and diastolic BP
Normal: about 1/3 of systolic blood pressure
High: atherosclerosis, exercise
Low: severe heart failure, hypovolemia
Pulsus alternans
Regular rhythm but strength of pulse varies with each beat.
Could possibly be due to heart failure
Hypertension
High blood pressure: pressure in your arteries is higher than it should be
Causes adverse effects to arterial walls which increases peripheral vascular resistance.
If left untreated it causes decreased blood flow.
Normal BP
Less than 120 AND less than 80
Elevated BP
120-129 AND less than 80
Hypertension stage 1
130-139 OR 80-89
Hypertension stage 2
140+ OR 90+
Hypertensive Crisis
Greater than 180 AND/OR greater than120
Hypertension symptoms
Dizziness, headache, blurry vision, heart palpitations, fatigue
Hypertensive emergency
- develops over hours or days
- BP above 220/140
- target organ disease
Hypertensive urgency
- develops over days to weeks
- BP above 180/110
- no target organ disease
Hypotension
Systolic blood pressure falls below 90
We want to know if the patient is symptomatic (if not then that might be there baseline)
We care because we want to know if the organs are getting perfused.
Causes of hypotension
- dilation of arteries
- loss of blood volume (hypovolemia)
- failure of heart muscle to pump
S/s of hypotension
- Skin: pallor, clammy,
- Decreased perfusion to the brain: lightheaded, dizzy (syncope), confusion,
- blurred vision
- chest pain
- increased HR
- decrease urine output (decreased perfusion to the kidney
- nausea/ vomiting
Orthostatic hypotension
SBP decreases 20+ mmHg
DBP decreases 10+ mmHg
Compensatory mechanisms normally in place does not work. Perfusion to the brain decreases going from sitting to standing position
Venous thromboembolism (VTE)
Obstruction of a blood vessel by a blood clot (thrombus) that has become dislodged into circulation (embolism).
Most commonly starts in the legs and moves to the lungs (pulmonary embolism)
Preload
The amount of blood in the left ventricle at the end of diastole, before the next contraction.
Afterload
The resistance to the ejection of blood from the left ventricle.
Diastolic pressure is a good clinical measure of afterload.
Myocardial contractility
The ability of the heart to squeeze blood from the ventricles. Affects stroke volume and cardiac output.
Infarction
Death of tissue resulting from a failure of blood supply.
